Light has been used in a wide range of medical applications for many years. In the field of dermatology high powered lasers and intense pulsed light (IPL) systems have been used to permanently remove unwanted hair, rejuvenate skin, remove veins etc. In the field of hair removal, devices remove hair from areas of the body with large diameter pulses of laser or incoherent light called intense pulsed light. One disadvantage of the above described devices is that the power (both electrical and light output) required to deliver permanent or long lasting results are extremely high, and such devices are only suitable for use in a clinical setting with trained professionals operating the devices. A further disadvantage is that the treatments are costly, painful, time consuming and only partially effective. To improve efficacy of these treatments more and more powerful devices have been marketed in an attempt to produce long lasting results. Additionally these devices utilize large diameter output beams which are known to penetrate the skin deeply and to deliver high doses of energy to the base region of the hair follicle. These newer devices which are capable of generating the “required” power level for effective long-term hair loss using a large diameter spots are large, heavy, expensive, require sophisticated cooling and are dangerous. Current prices on the market for such devices exceed $50K and the device itself can weigh more than 100 lbs. These are not devices that can be sold to individual consumers, or be operated safely in the home by average consumers.
In addition to the production of more powerful laser devices, a trend has also emerged toward larger spot sizes. Experimental results have shown that larger spots penetrate more deeply into tissue than small ones. Thus, researchers in this area, in an effort to obtain a long-lasting and more permanent result, strive to provide the larger sizes. Until now, little research has gone into understanding the actual behavior of light as it diffuses into tissue as it relates to the spot size. As a result, the use of small spot treatments has been dismissed as not feasible in this area of dermatology.
The commonly held (though incorrect) understanding of how light diffuses into skin as a function of spot size has prevented the industry from developing effective methods for hair growth modulation for the end consumer. The belief that only large diameter laser and IPL spots can cause hair loss has lead the entire industry to develop larger, more expensive and more dangerous devices; now producing more than 2900 W of output power.
The present invention relates to methods and devices that use a model for light diffusion in skin as a function of spot size. These methods and devices use a small spot size and low power radiation to achieve short-term hair growth modulation as well as for the treatment of other skin disorders. Furthermore the present invention demonstrates a device that can be highly effective using a fraction of the power required by today's typical devices. The device disclosed herein can be mass produced for safe use in the home with excellent results.